/*****************************************************************************
* pap.c - Network Password Authentication Protocol program file.
*
* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
* portions Copyright (c) 1997 by Global Election Systems Inc.
*
* The authors hereby grant permission to use, copy, modify, distribute,
* and license this software and its documentation for any purpose, provided
* that existing copyright notices are retained in all copies and that this
* notice and the following disclaimer are included verbatim in any
* distributions. No written agreement, license, or royalty fee is required
* for any of the authorized uses.
*
* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
******************************************************************************
* REVISION HISTORY
*
* 03-01-01 Marc Boucher <marc@mbsi.ca>
*   Ported to lwIP.
* 97-12-12 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
*   Original.
*****************************************************************************/
/*
 * upap.c - User/Password Authentication Protocol.
 *
 * Copyright (c) 1989 Carnegie Mellon University.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by Carnegie Mellon University.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include "lwip/opt.h"

#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */

#if PAP_SUPPORT /* don't build if not configured for use in lwipopts.h */

#include "ppp.h"
#include "pppdebug.h"

#include "auth.h"
#include "pap.h"

#include <string.h>

/***********************************/
/*** LOCAL FUNCTION DECLARATIONS ***/
/***********************************/
/*
 * Protocol entry points.
 */
static void upap_init(int);
static void upap_lowerup(int);
static void upap_lowerdown(int);
static void upap_input(int, u_char *, int);
static void upap_protrej(int);

static void upap_timeout(void *);
static void upap_reqtimeout(void *);
static void upap_rauthreq(upap_state *, u_char *, int, int);
static void upap_rauthack(upap_state *, u_char *, int, int);
static void upap_rauthnak(upap_state *, u_char *, int, int);
static void upap_sauthreq(upap_state *);
static void upap_sresp(upap_state *, u_char, u_char, char *, int);


/******************************/
/*** PUBLIC DATA STRUCTURES ***/
/******************************/
struct protent pap_protent = {
    PPP_PAP,
    upap_init,
    upap_input,
    upap_protrej,
    upap_lowerup,
    upap_lowerdown,
    NULL,
    NULL,
#if 0
    upap_printpkt,
    NULL,
#endif
    1,
    "PAP",
#if 0
    NULL,
    NULL,
    NULL
#endif
};

upap_state upap[NUM_PPP]; /* UPAP state; one for each unit */



/***********************************/
/*** PUBLIC FUNCTION DEFINITIONS ***/
/***********************************/
/*
 *  Set the default login name and password for the pap sessions
 */
void
upap_setloginpasswd(int unit, const char *luser, const char *lpassword)
{
    upap_state *u = &upap[unit];

    /* Save the username and password we're given */
    u->us_user = luser;
    u->us_userlen = strlen(luser);
    u->us_passwd = lpassword;
    u->us_passwdlen = strlen(lpassword);
}


/*
 * upap_authwithpeer - Authenticate us with our peer (start client).
 *
 * Set new state and send authenticate's.
 */
void
upap_authwithpeer(int unit, char *user, char *password)
{
    upap_state *u = &upap[unit];

    UPAPDEBUG((LOG_INFO, "upap_authwithpeer: %d user=%s password=%s s=%d\n",
               unit, user, password, u->us_clientstate));

    upap_setloginpasswd(unit, user, password);

    u->us_transmits = 0;

    /* Lower layer up yet? */
    if (u->us_clientstate == UPAPCS_INITIAL ||
        u->us_clientstate == UPAPCS_PENDING)
    {
        u->us_clientstate = UPAPCS_PENDING;
        return;
    }

    upap_sauthreq(u);    /* Start protocol */
}


/*
 * upap_authpeer - Authenticate our peer (start server).
 *
 * Set new state.
 */
void
upap_authpeer(int unit)
{
    upap_state *u = &upap[unit];

    /* Lower layer up yet? */
    if (u->us_serverstate == UPAPSS_INITIAL ||
        u->us_serverstate == UPAPSS_PENDING)
    {
        u->us_serverstate = UPAPSS_PENDING;
        return;
    }

    u->us_serverstate = UPAPSS_LISTEN;
    if (u->us_reqtimeout > 0)
    {
        TIMEOUT(upap_reqtimeout, u, u->us_reqtimeout);
    }
}



/**********************************/
/*** LOCAL FUNCTION DEFINITIONS ***/
/**********************************/
/*
 * upap_init - Initialize a UPAP unit.
 */
static void
upap_init(int unit)
{
    upap_state *u = &upap[unit];

    UPAPDEBUG((LOG_INFO, "upap_init: %d\n", unit));
    u->us_unit         = unit;
    u->us_user         = NULL;
    u->us_userlen      = 0;
    u->us_passwd       = NULL;
    u->us_passwdlen    = 0;
    u->us_clientstate  = UPAPCS_INITIAL;
    u->us_serverstate  = UPAPSS_INITIAL;
    u->us_id           = 0;
    u->us_timeouttime  = UPAP_DEFTIMEOUT;
    u->us_maxtransmits = 10;
    u->us_reqtimeout   = UPAP_DEFREQTIME;
}

/*
 * upap_timeout - Retransmission timer for sending auth-reqs expired.
 */
static void
upap_timeout(void *arg)
{
    upap_state *u = (upap_state*)arg;

    UPAPDEBUG((LOG_INFO, "upap_timeout: %d timeout %d expired s=%d\n",
               u->us_unit, u->us_timeouttime, u->us_clientstate));

    if (u->us_clientstate != UPAPCS_AUTHREQ)
    {
        return;
    }

    if (u->us_transmits >= u->us_maxtransmits)
    {
        /* give up in disgust */
        UPAPDEBUG((LOG_ERR, "No response to PAP authenticate-requests\n"));
        u->us_clientstate = UPAPCS_BADAUTH;
        auth_withpeer_fail(u->us_unit, PPP_PAP);
        return;
    }

    upap_sauthreq(u);  /* Send Authenticate-Request */
}


/*
 * upap_reqtimeout - Give up waiting for the peer to send an auth-req.
 */
static void
upap_reqtimeout(void *arg)
{
    upap_state *u = (upap_state*)arg;

    if (u->us_serverstate != UPAPSS_LISTEN)
    {
        return; /* huh?? */
    }

    auth_peer_fail(u->us_unit, PPP_PAP);
    u->us_serverstate = UPAPSS_BADAUTH;
}


/*
 * upap_lowerup - The lower layer is up.
 *
 * Start authenticating if pending.
 */
static void
upap_lowerup(int unit)
{
    upap_state *u = &upap[unit];

    UPAPDEBUG((LOG_INFO, "upap_lowerup: %d s=%d\n", unit, u->us_clientstate));

    if (u->us_clientstate == UPAPCS_INITIAL)
    {
        u->us_clientstate = UPAPCS_CLOSED;
    }
    else if (u->us_clientstate == UPAPCS_PENDING)
    {
        upap_sauthreq(u); /* send an auth-request */
    }

    if (u->us_serverstate == UPAPSS_INITIAL)
    {
        u->us_serverstate = UPAPSS_CLOSED;
    }
    else if (u->us_serverstate == UPAPSS_PENDING)
    {
        u->us_serverstate = UPAPSS_LISTEN;
        if (u->us_reqtimeout > 0)
        {
            TIMEOUT(upap_reqtimeout, u, u->us_reqtimeout);
        }
    }
}


/*
 * upap_lowerdown - The lower layer is down.
 *
 * Cancel all timeouts.
 */
static void
upap_lowerdown(int unit)
{
    upap_state *u = &upap[unit];

    UPAPDEBUG((LOG_INFO, "upap_lowerdown: %d s=%d\n", unit, u->us_clientstate));

    if (u->us_clientstate == UPAPCS_AUTHREQ) /* Timeout pending? */
    {
        UNTIMEOUT(upap_timeout, u); /* Cancel timeout */
    }
    if (u->us_serverstate == UPAPSS_LISTEN && u->us_reqtimeout > 0)
    {
        UNTIMEOUT(upap_reqtimeout, u);
    }

    u->us_clientstate = UPAPCS_INITIAL;
    u->us_serverstate = UPAPSS_INITIAL;
}


/*
 * upap_protrej - Peer doesn't speak this protocol.
 *
 * This shouldn't happen.  In any case, pretend lower layer went down.
 */
static void
upap_protrej(int unit)
{
    upap_state *u = &upap[unit];

    if (u->us_clientstate == UPAPCS_AUTHREQ)
    {
        UPAPDEBUG((LOG_ERR, "PAP authentication failed due to protocol-reject\n"));
        auth_withpeer_fail(unit, PPP_PAP);
    }
    if (u->us_serverstate == UPAPSS_LISTEN)
    {
        UPAPDEBUG((LOG_ERR, "PAP authentication of peer failed (protocol-reject)\n"));
        auth_peer_fail(unit, PPP_PAP);
    }
    upap_lowerdown(unit);
}


/*
 * upap_input - Input UPAP packet.
 */
static void
upap_input(int unit, u_char *inpacket, int l)
{
    upap_state *u = &upap[unit];
    u_char *inp;
    u_char code, id;
    int len;

    /*
     * Parse header (code, id and length).
     * If packet too short, drop it.
     */
    inp = inpacket;
    if (l < UPAP_HEADERLEN)
    {
        UPAPDEBUG((LOG_INFO, "pap_input: rcvd short header.\n"));
        return;
    }
    GETCHAR(code, inp);
    GETCHAR(id, inp);
    GETSHORT(len, inp);
    if (len < UPAP_HEADERLEN)
    {
        UPAPDEBUG((LOG_INFO, "pap_input: rcvd illegal length.\n"));
        return;
    }
    if (len > l)
    {
        UPAPDEBUG((LOG_INFO, "pap_input: rcvd short packet.\n"));
        return;
    }
    len -= UPAP_HEADERLEN;

    /*
     * Action depends on code.
     */
    switch (code)
    {
    case UPAP_AUTHREQ:
        upap_rauthreq(u, inp, id, len);
        break;

    case UPAP_AUTHACK:
        upap_rauthack(u, inp, id, len);
        break;

    case UPAP_AUTHNAK:
        upap_rauthnak(u, inp, id, len);
        break;

    default:        /* XXX Need code reject */
        break;
    }
}


/*
 * upap_rauth - Receive Authenticate.
 */
static void
upap_rauthreq(upap_state *u, u_char *inp, int id, int len)
{
    u_char ruserlen, rpasswdlen;
    char *ruser, *rpasswd;
    int retcode;
    char *msg;
    int msglen;

    UPAPDEBUG((LOG_INFO, "pap_rauth: Rcvd id %d.\n", id));

    if (u->us_serverstate < UPAPSS_LISTEN)
    {
        return;
    }

    /*
     * If we receive a duplicate authenticate-request, we are
     * supposed to return the same status as for the first request.
     */
    if (u->us_serverstate == UPAPSS_OPEN)
    {
        upap_sresp(u, UPAP_AUTHACK, id, "", 0); /* return auth-ack */
        return;
    }
    if (u->us_serverstate == UPAPSS_BADAUTH)
    {
        upap_sresp(u, UPAP_AUTHNAK, id, "", 0); /* return auth-nak */
        return;
    }

    /*
     * Parse user/passwd.
     */
    if (len < sizeof(u_char))
    {
        UPAPDEBUG((LOG_INFO, "pap_rauth: rcvd short packet.\n"));
        return;
    }
    GETCHAR(ruserlen, inp);
    len -= sizeof(u_char) + ruserlen + sizeof(u_char);
    if (len < 0)
    {
        UPAPDEBUG((LOG_INFO, "pap_rauth: rcvd short packet.\n"));
        return;
    }
    ruser = (char*)inp;
    INCPTR(ruserlen, inp);
    GETCHAR(rpasswdlen, inp);
    if (len < rpasswdlen)
    {
        UPAPDEBUG((LOG_INFO, "pap_rauth: rcvd short packet.\n"));
        return;
    }
    rpasswd = (char*)inp;

    /*
     * Check the username and password given.
     */
    retcode = check_passwd(u->us_unit, ruser, ruserlen, rpasswd, rpasswdlen, &msg, &msglen);
    BZERO(rpasswd, rpasswdlen);

    upap_sresp(u, retcode, id, msg, msglen);

    if (retcode == UPAP_AUTHACK)
    {
        u->us_serverstate = UPAPSS_OPEN;
        auth_peer_success(u->us_unit, PPP_PAP, ruser, ruserlen);
    }
    else
    {
        u->us_serverstate = UPAPSS_BADAUTH;
        auth_peer_fail(u->us_unit, PPP_PAP);
    }

    if (u->us_reqtimeout > 0)
    {
        UNTIMEOUT(upap_reqtimeout, u);
    }
}


/*
 * upap_rauthack - Receive Authenticate-Ack.
 */
static void
upap_rauthack(upap_state *u, u_char *inp, int id, int len)
{
    u_char msglen;
    char *msg;

    LWIP_UNUSED_ARG(id);

    UPAPDEBUG((LOG_INFO, "pap_rauthack: Rcvd id %d s=%d\n", id, u->us_clientstate));

    if (u->us_clientstate != UPAPCS_AUTHREQ) /* XXX */
    {
        return;
    }

    /*
     * Parse message.
     */
    if (len < sizeof(u_char))
    {
        UPAPDEBUG((LOG_INFO, "pap_rauthack: rcvd short packet.\n"));
        return;
    }
    GETCHAR(msglen, inp);
    len -= sizeof(u_char);
    if (len < msglen)
    {
        UPAPDEBUG((LOG_INFO, "pap_rauthack: rcvd short packet.\n"));
        return;
    }
    msg = (char*)inp;
    PRINTMSG(msg, msglen);

    UNTIMEOUT(upap_timeout, u);  /* Cancel timeout */
    u->us_clientstate = UPAPCS_OPEN;

    auth_withpeer_success(u->us_unit, PPP_PAP);
}


/*
 * upap_rauthnak - Receive Authenticate-Nakk.
 */
static void
upap_rauthnak(upap_state *u, u_char *inp, int id, int len)
{
    u_char msglen;
    char *msg;

    LWIP_UNUSED_ARG(id);

    UPAPDEBUG((LOG_INFO, "pap_rauthnak: Rcvd id %d s=%d\n", id, u->us_clientstate));

    if (u->us_clientstate != UPAPCS_AUTHREQ) /* XXX */
    {
        return;
    }

    /*
     * Parse message.
     */
    if (len < sizeof(u_char))
    {
        UPAPDEBUG((LOG_INFO, "pap_rauthnak: rcvd short packet.\n"));
    }
    else
    {
        GETCHAR(msglen, inp);
        if (msglen > 0)
        {
            len -= sizeof(u_char);
            if (len < msglen)
            {
                UPAPDEBUG((LOG_INFO, "pap_rauthnak: rcvd short packet.\n"));
                return;
            }
            msg = (char*)inp;
            PRINTMSG(msg, msglen);
        }
    }

    u->us_clientstate = UPAPCS_BADAUTH;

    UPAPDEBUG((LOG_ERR, "PAP authentication failed\n"));
    auth_withpeer_fail(u->us_unit, PPP_PAP);
}


/*
 * upap_sauthreq - Send an Authenticate-Request.
 */
static void
upap_sauthreq(upap_state *u)
{
    u_char *outp;
    int outlen;

    outlen = UPAP_HEADERLEN + 2 * sizeof(u_char)
             + u->us_userlen + u->us_passwdlen;
    outp = outpacket_buf[u->us_unit];

    MAKEHEADER(outp, PPP_PAP);

    PUTCHAR(UPAP_AUTHREQ, outp);
    PUTCHAR(++u->us_id, outp);
    PUTSHORT(outlen, outp);
    PUTCHAR(u->us_userlen, outp);
    BCOPY(u->us_user, outp, u->us_userlen);
    INCPTR(u->us_userlen, outp);
    PUTCHAR(u->us_passwdlen, outp);
    BCOPY(u->us_passwd, outp, u->us_passwdlen);

    pppWrite(u->us_unit, outpacket_buf[u->us_unit], outlen + PPP_HDRLEN);

    UPAPDEBUG((LOG_INFO, "pap_sauth: Sent id %d\n", u->us_id));

    TIMEOUT(upap_timeout, u, u->us_timeouttime);
    ++u->us_transmits;
    u->us_clientstate = UPAPCS_AUTHREQ;
}


/*
 * upap_sresp - Send a response (ack or nak).
 */
static void
upap_sresp(upap_state *u, u_char code, u_char id, char *msg, int msglen)
{
    u_char *outp;
    int outlen;

    outlen = UPAP_HEADERLEN + sizeof(u_char) + msglen;
    outp = outpacket_buf[u->us_unit];
    MAKEHEADER(outp, PPP_PAP);

    PUTCHAR(code, outp);
    PUTCHAR(id, outp);
    PUTSHORT(outlen, outp);
    PUTCHAR(msglen, outp);
    BCOPY(msg, outp, msglen);
    pppWrite(u->us_unit, outpacket_buf[u->us_unit], outlen + PPP_HDRLEN);

    UPAPDEBUG((LOG_INFO, "pap_sresp: Sent code %d, id %d s=%d\n", code, id, u->us_clientstate));
}

#if 0
/*
 * upap_printpkt - print the contents of a PAP packet.
 */
static int upap_printpkt(
    u_char *p,
    int plen,
    void (*printer) (void *, char *, ...),
    void *arg
    )
{
    LWIP_UNUSED_ARG(p);
    LWIP_UNUSED_ARG(plen);
    LWIP_UNUSED_ARG(printer);
    LWIP_UNUSED_ARG(arg);
    return 0;
}
#endif /* 0 */

#endif /* PAP_SUPPORT */

#endif /* PPP_SUPPORT */
